CATALYSTSL, METHOD OF PREPARING THESE CATALYSTS AND POLYMERIZATION PROSESSES WHEREIN THESE CATALYSTS ARE USED

摘要

A catalyst is prepared by combining, in a suitable solvent or diluent, at least one first component consisting of a bis(cyclopentadienyl) derivative of a Group IV-B metal containing at least one ligand capable of reacting with a second component, which second component comprises a cation which will irreversibly react with at least one ligand in said first component and a stabilizing anion comprising a plurality of boron atoms which anion is bulky and stable to any reaction involving the cation of the second component and sufficiently labile to permit displacement by an olefin, diolefin, and/or acetylenically unsaturated monomer, and (b) maintaining the contacting in step (a) for a sufficient period of time to permit the cation of said second component to react with said ligand in said first component thereby forming an active catalyst either as a direct product or as a decomposition product thereof. Many of the catalysts thus formed are stable and isolable and may be recovered and stored. The catalysts may be preformed and then used to polymerize olefins or the catalysts may be formed in situ during polymerization by adding the separate components to the polymerization reaction. The catalyst will be formed when the two components are combined at a temperature within the range from about -100.degree.C to about 300.degree.C. The catalysts thus prepared afford better control of polymer molecular weight and are not subject to equilibrium reversal. The catalysts thus produced are also less pyrophoric than the more conventional Ziegler-Natta olefin polymerization catalysts.